Spray head assembly

ABSTRACT

There is disclosed a spray head assembly for dispensing a liquid spray with air under pressure. An internal valve in the spray head closes for positively preventing dripping of the liquid when the air under pressure is stopped and a piston is provided and is responsive to the development of a back pressure within the spray head for opening the valve during a spraying operation.

O 1 United States Patent 1 1 3,561,680

I 72] Inventor Richard J. on 1 References Cited Baroda, Mich. UNITED STATES PATENTS 915 $2 1968 3,168,250 2/1965 Paasche 239 411x I e P s 1451 Patented Feb. 9. 1971 FOREGN PATENTS [73] Assignee Respond Inc. 1,496,800 8/1967 France 239/410 Baroda i Primary ExaminerM. Henson Wood, Jr. a corporatm of Assistant Examiner-Michael Y. Mar

Attorney-Olson, Trexler, Wolters & Bushnell SPRQY HEAD A SSEMBLY ABSTRACT: There is disclosed a spray head assembly for 6 Chums 2 Drawmg dispensing a liquid spray with air under pressure. An internal [52] US. Cl 239/411, valve in the spray head closes for positively preventing 239/413, 239/570 dripping 0f the liquid when the air under pressure is stopped [51] Int. Cl B05b 7/12 and a piston is provided and is responsive to the development [50] Field of Search 239/410, of a back pressure within the spray head for opening the valve during a spraying operation PATENIEU FEB 9 Ian v SPRAY HEAD ASSEMBLY The present invention relates to a novel spraying apparatus, and more specifically, to a novel spray head assembly.

While spray head assemblies of the type contemplated herein may be adapted for a variety of installations and for spraying many different kinds of materials, they are especially suitable for use in applying a liquid lubricant to the face of a die in a die casting machine. Spray heads have heretofore been proposed for such use, and while certain of these have been satisfactory for many installations, it has been found that, under certain conditions, problems have arisen. For example, it is desirable to spray a uniform coating without dripping onto the face of a die for insuring the desired quality in the finished product being cast. Furthermore, dripping of excess lubricant from a spray head on the floor or machine can be a significant fire hazard, particularly when low flash point materials are being used.

lt is an important object of the present invention to provide a novel spray head assembly capable of delivering an atomized spray of liquid having the desired uniformity and constructed so as positively to preclude the dripping of excess liquid at the end of a spraying operation.

Another important object of the present invention is to provide a novel spray head assembly of the above described type which is constructed so as to be efficient and effective in operation under adverse environmental conditions such as those which surround a die-casting machine.

Still another object of the present invention is to provide a novel spray head assembly of the above described type which is of rugged, efficient and economical construction.

Other objects and advantages of the present invention will become apparent from the following description and the accompanying drawing wherein:

FIG. 1 is a partial sectional view showing a spray head assembly incorporating features of the present invention and further schematically showing the assembly connected with sources of liquid to be sprayed and air under pressure; and

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1.

Referring now more specifically to the drawings wherein like parts are designated by the same numerals throughout the various FlGS., a spray head assembly l incorporating features of the present invention is shown in F IG. 1 connected to a source 12 of liquid to be sprayed and to a source 14 of air under pressure. A liquid supply line or hose 16 which may be relatively rigid or flexible extends from the source 12 and another air line or hose 18 which may also be rigid or flexible extends from the source 14. An air shutoff valve 20 of known construction is connected in the air line 18. It is to be understood that a variety of different materials may be supplied to the spray head from the source 12, but as previously indicated, it is particularly contemplated that the spray head assembly may be used for delivering lubricants to dies in a diecasting machine.

The spray head assembly includes body means 22 having a main body member 24. A supplementary body member or end cap 26 is threaded onto one end of the body member 24 for a purpose to be described below and another supplementary body member or fitting 28 is threaded into an opposite end of the body member 24.

The body means has .a generally central longitudinally extending passageway 30 therein which extends to an outlet partially defined by the aforementioned fitting 28. An inner or upstream end of the passageway 30 communicates with a laterally extending inlet port 32 which is connected by a fitting 34 threaded into the side of the body member 24 with the fluid supply line or conduit 16. The inlet port 32 has a relatively small diameter as compared with the internal diameter of the supply line for accomplishing a preliminary metering of the liquid flowing into the spray head.

The body means is provided with another inlet port 36 communicating with the passageway 30 at a point between the inlet 32 and the outlet end of the passageway. The inlet port 36 is connected with the air supply line 18 by a fitting 38. This fitting has a bore 40 therethrough defining an air inlet passage having a predetermined cross-sectional area.

A fitting 42 is mounted within the passageway 30. More specifically the fitting 42 has a threaded body 44 secured within a reduced diameter portion of the passageway 30 between the inlets 32 and 36. A sealing ring 45 is disposed between the body portion 44 and a face 46 formed internally of the body member 24 for preventing the passage of any liquid around the fitting 42. An inner end 47 of the fitting 42 is disposed adjacent the inlet 32. An elongated passageway or bore 48 extends through the fitting for conducting liquid to be sprayed from the inlet 32 substantially to the outlet end of the passageway 30. As shown in FIG. 1. an outer end portion of the fitting 42 is in the form of an elongated tubular section 50.

A nozzle member 52 is provided at the discharge end of the spray head assembly and is formed with a discharge orlfice 54 which may be of various shapes in order to obtain a desired spray pattern. The nozzle member or orifice means defines a chamber 56 between the opening 54 and the end of the fitting section 50, which chamber is in part provided by a tubular section 58 of the nozzle member which is threaded into the fitting 28. As shown in FIG. 1 the internal diameter of the chamber portion or passageway provided by the section 58 is slightly greater than the external diameter of the fitting section 50 which projects within the section 58 so as to define an annular air passageway or orifice 60. The overall crosssectional area of the passageway 60 is substantially less than the area of the air inlet passageway 40 for the purpose described below.

As will be understood, a spraying operation is initiated by directing air under pressure through the inlet port 40 into an enlarged chamber portion 62 of the passageway 30. The air then flows through the restricted passageway 60 past a terminal end 64 of the tubular section 50 for drawing liquid to be sprayed out through the passageway 48. The liquid is mixed with the air in the chamber 56 and is directed out through the opening 50 in an atomized condition.

in order to control the flow of liquid through the passageway 48, a valve seat element 66 is mounted in the fitting 42 at the inner end 46 thereof and is adapted to cooperate with a valve element 68. The seat 66 is formed from a tough, firm, yet relatively resilient and soft material such as nylon and presents a relatively sharp annular edge 70 for engagement with the valve element. The element 68 is formed from a material such as metal which is relatively hard as compared with the valve seat and is provided with a conical or pointed configuration as shown so as to engage the valve seat with substantially line contact. While the valve element 68 is mounted substantially concentrically with respect to the valve seat, an effective line contact seal between the element and the seat will result even in the event of a slight misalignment because of manufacturing tolerances and the like since the relatively soft seat material enables the edge 70 to yield for accommodating such misalignment of the valve element.

The spray head structure is provided with means for opening the valve element 68 at the start of a spraying operation but only after the air flow and pressure within the spray head has built up to a degree sufficient to insure proper spraying and atomization of the liquid. This means is also constructed for properly and securely closing the valve element in order to prevent dripping and sputtering of the liquid at the end of a spraying operation.

The means for actuating the valve element 68 comprises a stem 72 to which the valve element is connected or with which it is integrally formed. The stem is slidably disposed in a bore 74 which is sealed by an O-ring 76. The stem extends rearwardly into a chamber 78 formed in the body means and is connected to or integrally formed with a piston 80 slidably disposed within the chamber and having its periphery sealed by an O-ring 82. A compression spring 84 is arranged between the piston and an end wall 86 of the body means and cap 26 for biasing the piston and thus the valve element toward the right in P10. 1 so that the valve element normally and sealingly engages the seat 70.

In order to actuate the piston for opening the valve element, an air passage 87 is formed in the body means for establishing communication between the chamber 62 and the chamber 78. Thus, when the air valve is opened at the start ofa spraying operation and air is introduced through the inlet port 40 into the chamber 62, the flow of spraying and atomizing air through the annular outlet passageway 60 is initiated, but at the same time, a back pressure builds up within the chamber 62, the passageway 87 and the piston chamber 78. As previously indicated, the effective crosssectional area of the annular outlet passageway 60 is substantially less than the area of the inlet port 40 so as to provide a restriction to the outward flow of the air, This causes the back pressure to build up sufficiently in the chamber 78 to actuate the piston against the force of the spring 84 to open the valve and permit the outward flow of the liquid to be sprayed. At the same time, the effective area of the passageway 60 is sufficient to enable an adequate flow of atomizing air to be established through the nozzle before the back pressure causes the valve element 68 to be opened. It is observed that the effective area of the discharge opening 54 in the nozzle is greater than the area of the passageway 60 so as to avoid the build up of an undesirable back pressure within the chamber 56.

The valve element 68 functions not only to control starting and stopping of the flow of liquid to be sprayed, but also as a metering device for enabling the flow rate of the liquid to be measured and adjusted independently of the flow of the actuating air. More specifically, adjustable means is provided for limiting the amount which the valve element 68 can be opened. As shown in FIG. 1, this means comprises an adjustable stop element or screw 88 threaded through the end wall 86 of the body means and having an inner end 90 positioned for engagement with the piston 80. A loeknut 92 is tightened onto the screw 88 for securing it in a desired adjusted position.

While a preferred embodiment of the present invention has been shown and described herein it is obvious that many structural details may be changed without departing from the spirit and scope of the appended claims.

I claim:

1. A spray head comprising: body means including passageway means therein; discharge orifice means connected with said passageway means; a first inlet for material to be sprayed connected with said passageway means upstream from said orifice means; a second inlet having a predetermined cross-sectional area for actuating air and connected with said passageway means between said orifice means and said first inlet; means providing an air restriction having a cross-sectional area less than said predetermined area between said orifice means and said second inlet; a valve seat disposed in said passageway means between said inlets; a valve element engageable with said seat for blocking said passageway means and preventing the fiow of material to be sprayed therethrough; said body means including a chamber behind said valve element and communicating with said air inlet; a piston slidable in said chamber and connected with said valve element; said piston being operable by back pressure provided by the actuating air for opening said valve element and spring means within said body means and engaging said piston for normally biasing the valve element against the valve seat; said valve seat comprising an element of relatively soft material presenting an annular edge; and said valve element being formed of relatively hard material.

2. A spray head, as defined in claim 1, which includes an adjustable stop element mounted in said body means and projecting into said chamber for engaging said piston and limiting opening of the valve element for controlling the flow of material to be sprayed 3. A spray head, as defined in claim 1, wherein said valve seat element is formed of plastic. said valve element being pointed and engaging said edge with substantially line contact.

4. A spray head comprising: body means including passageway means therein; discharge orifice means connected with said passageway means; a first inlet for material to be sprayed connected with said passageway means upstream from said orifice means; a second inlet having a predetermined cross-sectional area for actuating air and connected with said passageway means between said orifice means and said first inlet; means providing an air restriction having a cross-sectional area less than said predetermined area between said orifice means and said second inlet; a valve seat disposed in said passageway means between said inlets; a valve element engageable with said seat for blocking said passageway means and preventing the flow of material to be sprayed therethrough; said body means including a chamber behind said valve element and communicating with said air inlet; a piston slidable in said chamberand connected with said valve element; said piston being operable by back pressure provided by the actuating air for opening said valve element; and spring means within said body means and engaging said piston for normally biasing the valve element against the valve seat; said body means comprising a main body member having said passageway means therein; said passageway means including a first section and a second larger diameter section defining a chamber; said orifice means comprising a nozzle member having a discharge orifice at its outer end and a tubular inner end extending into said chamber and having a predetermined internal diameter; a fitting mounted within said body member and including a first portion in said first passageway section and having said valve seat thereon and a second tubular portion extending into said tubular nozzle section and having an external diameter less than said predetermined diameter and cooperating with said tubular nozzle section for providing said air restriction; said fitting having abore extending therethrough from the valve seat and communicat ing with the nozzle.

5 A spray head, as defined in claim 4, wherein said body means includes a supplementary body member connected with-said main body member and cooperating therewith in defining said first mentioned chamber, said spring means comprising a compression spring disposed between an end wall of said supplementary body member and said piston.

6. A spray head, as defined in claim 5, which comprises an adjustable stop element extending through said end wall of the supplementary body member for engaging the piston and limiting opening movement of the valve element for controlling the rate of flow of the material being sprayed during a spraying operation. 

1. A spray head comprising: body means including passageway means therein; discharge orifice means connected with said passageway means; a first inlet for material to be sprayed connected with said passageway means upstream from said orifice means; a second inlet having a predetermined cross-sectional area for actuating air and connected with said passageway means between said orifice means and said first inlet; means providing an air restriction having a cross-sectional area less than said predetermined area between said orifice means and said second inlet; a valve seat disposed in said passageway means between said inlets; a valve element engageable with said seat for blocking said passageway means and preventing the flow of material to be sprayed therethrough; said body means including a chamber behind said valve element and communicating with said air inlet; a piston slidable in said chamber and connected with said valve element; said piston being operable by back pressure provided by the actuating air for opening said valve element and spring means within said body means and engaging said piston for normally biasing the valve element against the valve seat; said valve seat comprising an element of relatively soft material presenting an annular edge; and said valve element being formed of relatively hard material.
 2. A spray head, as defined in claim 1, which includes an adjustable stop element mounted in said body means and projecting into said chamber for engaging said piston and limiting opening of the valve element for controlling the flow of material to be sprayed.
 3. A spray head, as defined in claim 1, wherein said valve seat element is formed of plastic, said valve element being pointed and engaging said edge with substantially line contact.
 4. A spray head comprising: body means including passageway means therein; discharge orifice means connected with said passageway means; a first inlet for material to be sprayed connected with said passageway means upstream from said orifice means; a second inlet having a predetermined cross-sectional area for actuating air and connected with said passageway means between said orifice means and said first inlet; means providing an air restriction having a cross-sectional area less than said predetermined area between said orifice means and said second inlet; a valve seat disposed in said passageway means between said inlets; a valve element engageable with said seat for blocking said passageway means and preventing the flow of material to be sprayed therethrough; said body means including a chamber behind said valve element and communicating with said air inlet; a piston slidable in said chamber and connected with said valve element; said piston being operable by back pressure provided by the actuating air for opening said valve element; and spring means within said body means and engaging said piston for normally biasing the valve element against the valve seat; said body means comprising a main body member having said passageway means therein; said passageway means including a first section and a second larger diameter section defining a chamber; said orifice means comprising a nozzle member having a discharge orifice at its outer end and a tubular inner end extending into said chamber and having a predetermined internal diameter; a fitting mounted within said body member and including a first portion in said first passageway section and having said valve seat thereon and a second tubular portion extending into said tubular nozzle section and having an external diameter less than said predetermined diameter and cooperating with said tubular nozzle section for providing said air restriction; said fitting having a bore extending therethrough from the valve seat and communicating with the nozzle.
 5. A spray head, as defined in claim 4, wherein said body means includes a supplementary body member connected with said main body member and cooperating therewith in defining said first mentioned chamber, said spring means comprising a compression spring disposed between an end wall of said supplementary body member and said piston.
 6. A spray head, as defined in claim 5, which comprises an adjustable stop element extending through said end wall of the supplementary body member for engaging the piston and limiting opening movement of the valve element for controlling the rate of floW of the material being sprayed during a spraying operation. 